Boiler-control system



Patented Aug. 20,

UNITED STATES- PATENT oEElcE.

WARREN DOIBLE, OF'SAN IRANCISCO, CALIFORNIA, ASSIGNOR TO DOBLE LABORA-TORILES, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

BOILER-CONTROL SYSTEM.

Original application filed December 13, 1919, Serial No. 344,741.Divided and this application filed November 20, 1923.

, This invention relates to a system for controlling the temperature andpressure conditions in a steam boiler, and more particularly to such asystem in which the water or other heat absorbing medium is supplied tothe boiler automatically in accordance with prescribed conditionsoftemperature and pressure.

This application is a division of an application filed Dec. 13, 1919 inmy name,

entitled Steam power plant control and having Serial No. 344,741, nowPatent No. 1,481,460. 1

,It is one of the objects of my invention to prevent undue temperatureor pressure rise in a boiler by properly controlling the intake of thefeed water. This is of especial importance in boilers that are adaptedto operate the engines for propelling automo- 2 biles, since theconditions imposed upon such engines are not only exceptionally severe,but also vary rapidly.

It is another object of my invention to provide an electromagneticallycontrolled source of liquid supply, in which the electric circuits areoperated in response to a combination of pressure and temperatureconditions in the boiler;

My invention possesses other advantageous features, some of which withthe foregoing, will be set forth at length in the following description,where I shall outline in full that form of the invention which I haveselected for illustration in the drawing accompany- 85 ing and formingpart of the present specification. Although I have shown in the drawingbut one embodiment of my invention, I do not desire to be limitedthereto, since the invention as expressed in the claims may be embodiedin other forms also.

Referring to the drawing:

The single figure is a diagrammatic representation of an installationembodying my invention.

In the present instance the boiler 1 is heated by the combustion ofliquid fuel, such as kerosene, distillate, or oil. In order to vaporizethe fuel so that it may serve most efficiently as a heat producingmedium, it is conducted to arotating cup 2 through a pipe or conduit 3,leading from a small tank 4 which in turn connects to a source of supplyby the aid of a pipe 5. The cup 2 is Serial No. 75,850.

.inent for supplying it with the liquid to e heated therein. Anappropriate form of such a device is diagrammatically illustrated, andcomprises a reciprocating pump 10, its discharge being connected as bypipe llto the boiler, and, arranged to be driven by the crank and roddevice 12. This device is coupled to the engine operated from theboiler, so that the operative parts of pump 10 are continuously inmotion during the operation of the engine. The intake to the pump iscontrolled by) a valve 13 in a chamber 14 connected as y pipe 15 to asource of liquid. The valve is so arranged that it seats whenever thepump 10 is on .its dischargestroke, but unseats in. response to thereduction .in pressure above it, when the pump is on its suction stroke.This type of pump as thus described, may readily be rendered inactive,irrespective of the movement of the parts 12, by moving and retainingthe valve 13 in its unseated position. By holding the inlet valveunseated, the pump is rendered inoperative to introduce water into theboiler. A check valve 60 in the pipe 11, betweenthe boiler and the pumpre vents discharge of water from the boiler. One method by which theinlet valve is retained in its unseated position, in response todefinite temperature and pressure conditions Within boiler 1, will bedescribed hereinafter in detail.

The pressure and temperature controLdevices are also used to affect theoperation of the liquid fuelburner. The pressure controllin device,which is merely diagramniatica ly illustrated, includes a mechanicallymovable lever 16, the position of which is dependent upon the pressureexisting in .the boiler 1. This may be accomplished for example bythe'aid of a cylinder 17 which is connected to the boiler 1, and whichhas a piston 18 mechanically attached to the lever 16. An increase inpressure causes lever 16 to rock in a clockwise directionagainst gravityor a spring 16*. The lever is so arranged that its movement regulatesthe flow of fuel to the cup 2, as by aid of a valve 19 and a connection20. Inorder to ensure complete combustion at all times, and that noexcess air is supplied to absorb heat wastefully, another mechanicalconnection 21 may be provided to a butterfly valve 53 which controls theamount of air that can be supplied to the combustion chamber throughpassageway 7, air is discharged by the blower 9 through the passage 7into the combustion chamber, 'the air flowing to the blower through theopening 22 and past the rotating cup 2. The simultaneous, continuouscontrol of the fuel intake and the air intake en-- due to variations intemperature. The move ment ofthe outer end of the rod is caused. tooperate electrical contacts, such as 25 and 26, which cooperate withstationary, spring pressed contacts 27 and 28. The-contacts 25 and 26are arranged on a disk 29 carried byv the end of the rod. Thetemperature control is such that an excessive or dangerous rise .intemperature is prevented. The con tacts 26 and 28 serve to control thefuel feed, the supply of air and the circuit of the blower motor, andare so adjusted that they effect this controllin only upon the existenceof undesirable fiigh temperatures.

The arrangement by which this result is accomplished may take the formof an electromagnetically operated valve 30 in the fuel tank 4. Thisvalve is arranged to'be urged, as by gravity, to its seated position,whereb it closes the fuel supply pipe 3,but it is held; during normaloperation, awa from its seat by the aid of a solenoid 31. he energizingcircuit for this solenoid may be traced as follows: from a common groundreturn 32, to a source of electrical energy 33, a manually operableswitch 34, connection 35, a pair of normally closed contacts 36 (whichopen only in response to excessive pressure conditions, operating on arm16 mechanically controlling these contacts), connection 37, contacts 26and 28, connection 38, solenoid 31, and ground 39. By this arrangementthe flow of fuel will be interrupted by valve 30 When- I is opened atthese contacts. Theenergizing i circuit for motor 8 may be traced asfollows: from ground 32, to source of electricity 33, switch, 34,connection 42, contacts 41 and 40, motor 8, back to ground at 43.

The control of the feedwater pump 10 'will'now be described. Normallythe valve 13 is permitted tofollow the reciprocations of this pump, toseat and unseat on the discharge and suction stroke respectively. Asolenoid 44 is arranged to be energized to hold the valve unseated andthus render the pump 10 inactive. This occurs whenever the pressure inthe boiler rises, to an objectionably high value, and is accomplished bythe aid of a stationary contact 45 and a contact 46 movable inaccordance.- with the movement of lever arm 16. When this arm moves asubstantial distance in response to a predetermined increase in pressurein boiler -1, the contacts 45, 46 close, and the solenoid 44 isenergized, unseating the valve 13 and disabling the pump until thepressure is reduced to a normal value. The energizing circuit for thesolenoid 44 may be traced as follows: from-ground 32, to source ofelectricity 33, switch 34, connection 47, contacts 46-and 45, connection48, connection 49, solenoid 44, and ground 50. It is to be noted at thispoint that the contacts 45 and 46 are operated whenthe excessivepressure in the boiler is caused for example by the introduction ofwater by the feed pump, as when the automobile upon which the boiler isinstalled is traveling down a long grade, and the engine is turningover, operating the ump 10.

eans are also provided for controlling the introduction of feed waterinto the boilerby temperature conditions within the boiler, to preventflooding of the boiler when the temperature therein is low. This isaccomplished by rendering the pump 10 inoperative to pump water when theboiler temperature is below the predetermined minimum. Connected to thesolenoid 44,

.which controls the valve 13 of the pump, is

a temperature controlled circuit 515249 which is connected in parallelwith the pressure control circuit. The contacts 25 and 27, the relativepositions of which are controlled by boiler temperature conditions, arearranged in the circuit 5152-49. When the temperature of the boilerfalls below the for supplying predetermined minimum, the contacts 25 and27 are brought into engagement, closing the circuit through the solenoid44, raising the valve 13 from its seat and rendering the" pump inactive.When the temperature subsequently rises above the predetermined minimum,the contacts 25 and 27 are separated, the solenoid 44 is de-energizedand the pump functions to introduce water into the boiler. d

The operation of the system is as fol-, lows: to set the boiler intooperation, it is necessary to close the switch 34, either manually or inany other way. The valve 30 will then be opened, to permit fuel to feedto the cup 2, the control circuit for this valve being closed atcontacts 36, and 26 28. The opening of valve 30 causes contacts 40 and41 to close, and the motor 8 is energized thereby. Fuel is thenvaporized by cup 2 and is projected into the combustion chanber by thefan 9 where it is ignited by any suitable device. The boiler 1 is now infull operation. By aid of valve 19, the pressure is maintained withinthe desirable predetermined limits. However, in case this pressure forany reason becomes too high, .the circuit for electromagnet 31 isabruptly interrupted at contacts 36 and the burner becomes inoperative.At the same time pump 10 is inactive due to engagement of contacts 45and 46. Upon a return to normal pressure, the flow of fuel and operationof motor 8 is automatically resumed. Excessive temperatures will alsodisable the burner apparatus, by aid of rod 23 and contacts 26-28.Regulation of boiler temperature is also effected by the aid of contacts25-27, and solenoid 44, as has been already described. The pump 10cannot function unless the temperature is above a definite lower limitimposed by these contacts, and unless the pressure is below a definitehigher limit imposed b contacts 45 and 46. It is thus seen that teactuation of puinp 10 isaccomplished only when the system de mands it.a

I claim:

1. In combination, a liquid heater, continously operating means forsupplying liquid to said heater, an electrical translating devicearranged, in response to variations in its energization, to control theliquid supply, and means responsive to both pressure andtemperaturevariations in the heater for varying the energization of said device.

2. In combination, a liquid heater, continuously operating means forsupplying liquid to said heater, a'solenoid for controlling the flow ofliquid to the heater, and means responsive to both pressure andtemperature variations in the heater for controlling the solenoid.

3. In combination, a liquid heater, means liquid to the heater, anelectrical translating device, arranged, in response to variations inits energization, to control the liquid supply, means responsive totemperature below a set limit within the heater for actuating thetranslatin device to interrupt the liquid supply, an means responsive topressure within the heater above a set limit for actuating the device tointerrupt the liquid supply.

4. In combination, a liquidheater, means for supplying liquid to saidheater, a solenoid for controlling the flow of liquid to the heater, anelectric energizing circuit for the solenoid, means responsive totemperature within the heater below a set limit for affecting thiscircuit in such a way that the solenoid interrupts the liquid supply,another electric circuit for the solenoid, and means responsive topressure within the heater above a set limit for controlling this lattercircuit to cause the solenoid to interrupt the liquid supply.

5. In combination, a liquid heater, means for supplying liquid to theheater, a solenoid for controlling the flow of liquid to the heater, apair of circuits in parallel for independently energizing said solenoid,means respon sive to pressureconditions within the heater forcontrolling one of the circuits, and means responsive to temperatureconditions within the heater for controlling the other circuit.

6. In combination, a liquid heater, a reciprocating pump for supplyingliquid to the heater, an intake valve for the pump ar-" ranged to bealternately opened and closed on the intake and discharge strokesrespectively, and means for maintaining the valve open in response totemperature and pressure conditions within the heater.

7. In combination, a liquid heater, a reciprocating pump for supplyingliquid to the heater, an intake valve for the pump are ranged to bealternately opened and closed on the intake and discharge strokesrespectivly, means for maintainingv the valve open in response to atemperature'in the heater below a set limit, and means for maintainingthe valve open in response to a pressure in the heater above a setlimit.

8. In combination, a liquid heater, a reciprocating pumpfor supplyingliquid to the heater, an intake valve for the pump arranged to bealternately opened and closed on the intake and discha e strokesrespectively, a solenoid arranggd when energized to maintain the valveopen, means for energizing the solenoid in response to a temperature inthe heaterbelow a set limit, and another means for energizingthesolenoid in response to a pressure in the heater above a set limit.

9. The combination with a heat absorbing medium containing device, of apump for forcing water into said device, a valve for controlling theflow of water into the device, a solenoid for operatin said valve, theenergizing of the solenoi serving to stop the flow of water into thedevice, means operative by an increase in pressure in the device to apredetermined pressure for energizing the solenoid and means operativeby an increase in temperature in the device to a predeterminedtemperature for deenergizing the solenoid.

10. In combination, a fluid heater, 8. pump having a valve,electro-magnetic-means for making-the valve inoperative, thereb makuidto ing the pump ineffectual to pump the heater, the electro-magneticmeans being controlled by variations in temperature and pressure in thefluid heater.

30 whereof, I have hereunto set WARREN DOBLE.

